Method for detinning and producing tin compounds and other products.



No. 875,632. PATENTED DEC. 31, 1907. E. A. SPBRRY. METHOD FOR DETINNING AND PRODUCING TIN COMPOUNDS AND OTHER PRODUCTS.

APPLICATION FILED AUG. 24, 1907.

2 SHEETS-SHEET 1- [NVENTGR Af/ameyd No. 875,632. PATENTED DEC. 31, 1907.

I B. A. SPERRY. METHOD FOR DETINNING AND PRODUCING TIN COMPOUNDS AND OTHER PRODUCTS.

APPLICATION FILED AUG.24,1907.

2 SHEETS SHEET 2.

agVVE/VTOR UNITED STATES PATENT orrion.

ELMER A. SPERRY, OF BROOKLYN, NEW YORK.

METHOD FOR DETINNING AND PRODUCING TIN COMPOUNDS AND OTHER PRODUCTS.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Original application filed November 29. 1905. Serial No- 289581. Divided and this application filed August 24, 1907. Serial No. 389,953.

To all whom it may concern:

Be it known that I, ELMER A. SPERRY, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented new and useful Improvements in Methods for Detinning and Producing Tin (10m ounds and other Products, of which the ollowing is a specification.

This invention is based on the chemical reaction between chlorin and metallic tin which produces stannic chlorid. Tin or any tin bearing material, such for instance as tin plate scrap, may be considered as suitable for the supply of the metal.

The invention consists in a process or method of operation whereby chlorin in any of its reacting forms, including anhydrous chlorin, gaseous chlorin, pure or diluted with moisture, or other gases or va ors or chlorin compounds may be successful y employed in carrying out the process economically, continuously and on a commercial basis. The stannic chlorid immediately resulting from the reaction may be considered as the terminal roduct, but'the invention extends to half of a basket.

phiyed t also consists in the preliminary treatment of the scrap and in various steps of treatment of bothscra and product throughout the operation of t e process, all of which are peculiar to my process, being described in full detail herein, and pointed out in the claims attachedhereto and forming a part thereof.

The accompanying drawings serve the purpose of illustrating one form of apparatus with which the process may be carried into .efl'ect.

In these drawings Figure 1 illustrates a' Fig. Zia two half baskets, assembled into a spherical package ada ted to contain tightly compacted tin scrap. ig.

3 represents a diagrammatic view of suitable means for carrying out the process; this figure is continued on the second sheet. Figs. 4 and 5 are details illustrating parts of the apparatus by means of which the process is carried forward.

Before going into a detailed description of the process, it may be well to explain that in the successful detinning of tin scra it is necessary not only to cover the tin but to completely strip the scrap of tin and if 0ssible of all other foreign metals, inasmuc as scra containing more than .04 per cent. of foreign metals is unfit for pur osel of making steel, and therefore of very ittle value as there is practically no market for impure scrap. Again the surface of the scrap should be attacked or'oxidized as little as possible. Again, the rocess should be as continuous as practica le, in this manner avoiding unnecessary expense for labor. In attaining these objects I avail myself, among other things, of a discovery which I have made that hydrated stannic chlorid and stannic chlorid solutions, es ecially when containing chlorin are extreme y active in dissolving or separating tin from other metals or from tin bearing materials, such as tin plate, but the solutions of stannic chlorid are extremely corrosive and do not suspend their action when the tin has disa peared from the iron orsteel plate but go arther and attack the plate itself. I have discovered, however, that this is not true to any appreciable extent when the attack is made by hydrated stannic chlorid, under seal of anhydrous stannic chlorid all in the resence of the latter, though not necessari y at all times under seal thereof. This contemplates the admission of water less than that required to make solution.

So far as I have been able to ascertain the increase in the activity of both the hydrate and the solutions of stannic chlorid is. as follows Beginning with the hydrate containing three waters of crystallization as increasing amounts of water are added until a point at about fifty to forty degrees on the Baumscale (for liquids heavier than water) is reached 'uids is also greatly increased by the agitation, especially in the presence of the incoming chlorin or gases containing chlorin.

I have also discovered that fused stannlc chlorid hydrate constitutes an electrolyteand is slftable inpoints of electric conductivity and activity for use as such,'. and I find that by so utilizing this function of thehydrate I am enabled to. more completely strip the scrap and free it from foreign metal content than by simple chlorination. The electrolization also tends to correct any tendency of the liquids to pass from the stannic to the stannous state.

The recovery of tin is also greatly facilitated by utilizing the hydrate as an electrolyte. I thus render a material or combination of materials in liquid state more active than hydrous stannic chlorid doubly active by use of the electric current, a thing impossible with the anhydrous, inasmuch as it is a non-conductor of electricity. I thus develop conditions which are extremely favorable to the complete removal of all foreign materials inasmuch asmaking the scrap the anode in such a'bath helps to remove the last traces of tin, together with some other metals, such for instance, as lead and antimony. The presence-of the hydrate again is found extremely advantageous in the ractical operation of the rocess as it avoir s the necessity of drying t e chlorin, as complete drying is necessary when the anhydrous chlorid is exclusively employed. I

In the present process I am enabled to 'use ordinary wet chlorin even when associated with air or other gases which themselves may bring water into the system, and instead of drying, which is most difficult and expensive with chlorin gas I may under some circumstances inject extra water; and moreover the process goes forward completely under conditions as stated Where an or gases are entrained with the chlorin, as provision is made for recovering all values which are taken from the system either as gases or vapors and which may be either entrained, dissolved or taken up by such air or gases; this step in the process forms an essential partthereof.

In the preliminary preparation of the scrap, it may be divided into; two classes; cuttings, which is usually from new tin plate, and manufactured scrap, which is for the most art old scrap, such as cans, etc. in some lnstances no classification is made.

The scrap may be put through the process in any form thought desirable, in mass or rammed tightly into retainers, as illustrated herein. The first class is put into the retainers or baskets direct. The second class may have revious treatment before being placed in t icse baskets. This treatment if used consists first in a rough mechanical The baskets ar' practically made of steel net or wires meri ianally disposed and secured to a circular ring at the joint. l The rings are detachably secured to each other. The tin scrap or cuttings are now preferably washed in a bath of caustic alkali in tank B, drained in tank C, and dried in oven D atan elevated temperature, whereupon they are in readiness to join the other baskets A, in the farther steps of the operation and preferably while still heated from the drying process.

In nearly all the steps it is designed to handle these spherical containers filled with scrap automatically, and to this end a number of devices may be employed for rolling or otherwise causing motion to be imparted to these spheres in their transit through the various stages or rocessh may be employed is a device similar to a hollow revolving screen which is slightly inclined from end to end, upon the revolving One means that o of which the spheres introduced at one end gradually work their way to the other, after having rotated in practically every plane possible through the double motion thus imparted to the spheres. valuable from thefact that especially in some of the steps of the process, such for instance, as drying and evaporating, the universal motion imparted serves to dump and eject any material which would otherwise be trap ed and retained in an angle or corner of t e compacted scrap as packed and retained in this state as by the containers A. In this state the agitation or motion is also effective in eliminating any air that may be entrapped or entrained as the hot masses, much hotter in fact than the reaction chamber itself, are introduced therein under seal the agitation is, also very advantageous in The rotation is V aidingthe distribution and absorption of the chlorin tlrronghout the anhydrous liquid or liquids present, thus not only preventing thesame agitation. These revolving screens may be made of iron, inasmuch as under the conditions here presented, iron is not attacked by the chemical reactions or in any other manner to an appreciable extent.

After the baskets and scrap are dried and preferably while yet hot, they are introduced from the drier D into the tube E, which terminates below the surface, of liquid 0,.

which is of some height, for the purpose of preventing the egress of fumes contained in the vessel E, in which is a revolving screen a, handling the spheres A, A, A, etc., for the most part below the surface of the chlorid. The revolving of this screen, or part a, also serves to agitate the chlorid, which thus greatly aids in presenting freshly chlorinated liquid to the tinned surfaces.

The rotation maybe effected through a wheel E coming out through a stufling box b. The whole is inclosed within a steam or other jacket F, by means of which the temperature of the chlorid c is governed. This jacket may be either heat-absorbing as when containing water or heat-emitting as when containing steam according to the necessities of the case; By their aid the contents may be held at any temperature required, preferably above the congealing point of the stannic hydrate with 3 or 5' waters of hydration, including considerations such as, primarily, the vigor of the reaction, also size of apparatus, radiating surface, etc. The chlorin or gases containin chlorin which may or may not be comming led with water or water vapors are introduced into tank E, through pipe G and the surplus liquids drawn off through pipes H or H; the former being at the over flow level of the tank E. The surplus gases are suitably drawn ofi as b jacketed pipe E leading to compartment The revolving screen is insulated at. its points, a and a" and stuffing box b, so that as the spheres are revolving in the screen a, an electric current is passed into the screen including the spheres, which thus become anodic through the virtue of the hydrated stannic chlorid present which acts in thecapacity of an electrolyte, as described.

The lead that becomes electrically separated from the scrap falls to the bottom of the tank E, while the tin which tends to attach itself to the cathode or plate thereon is immediately seized upon by the excess chlorin dissolved or otherwise held in the. bath and converted together with any stannous chlorid into stannic chlorid.

The further steps of the rocess are very simple and consist of suita ly ejecting the spheres from the revolving screen a, and t irough an opening E leading to the washing compartment 1, which is shown as being furnished with anotherrevolving screen a where the spheres are washed in an anhydrous liquid preferably anhydrous stannic are passed to the chamber which is maintained preferably at a temperature of 116 degrees or above, where the scrap is drained, evaporated and dried, and thus freed from the washing liquor together with any stannic chlorid which may still cling to them. It is here where the revoluton and universal motion referred to above, through all planes is also advantageous as any pocketed chlorid may escape and be drawn or driven off during this process of evaporation. If any hydrate remains from the washing in anhydrous liquids, it is found to evaporate very rapidly at a suitable temperature. The vapors and gases-passing from this chamber especially with t e vaporizing anhydrouschlorid present, also the vapors from the washing liquid, are lead in jacketed pi es as pipe K, held at a temperature prefer'ab y eighty (80) degrees or more, to a condenser or condensers L, where the gases are suddenly cooled and Where both the anhydrous liquid'or liquids.

and-J, which are connected by the jacketed passages as shown. Any residual gases assing from any of these tanks and throug the condensers L, are lead in the jacketed pipe N to the tower T, and there treated with a suitable solvent for the vapors or gases passing, as, for instance, when anhydrous chlorid is present water may be employed, in a. suitable manner for production of solutions of stannic chlorid.

A plurality of condensers is employed and valves Z and 1 provided so that one may be shut ofi and freed of any solids such as crystals and hydrate, while the other is con- (lensing.

It will be seen that the function of condenser L, is twofold, as reviously stated by me in another branch 0 this art in connection with the production of anhydrous stannic chlorid, namely, that of both condensing and separating hydrated and anhydrous stannic chlorid one from the other, the crystals remaining upon the walls of the con-' denser, while the anhydrous trickles down and is removed either mechanically'or by heating above its melting point, whereupon it runs out and is caught 'in receptacle M. It will thus be seen that the products are first heated to insure liquefaction of the hydrate, which otherwise is found to deposit and plug the pipes solidly, afterward they are cooled to condense the vapors and also to solidify and thus separate the hydrated from the anhydrous stannic chlorid, as hereinbe fore stated. v

A suction fan or blower O .is shown connected with the tower, which produces the necessary movement of the gases throughout the system, and is practically so adjusted as by using .the valve 0 that the pressure .is

almost at equilibrium with the surrounding atmosphere throughout the system, same be ing preferably somewhat inhalent or negative, to avoid emission 'of'the gases and vapors.

It now remains to explain the treatment of the products, which are hydrated and anhydrous stannic chlorid and solutions thereof. These where associated, as from tank E, are first strained 0r filtered hot to freethem from foreign materials, then allowed to cool and again strained, whereu on the hydrate which has become crysta lized at thelower temperature, is separated from the anhydrous. cleansed in any suitable manner. This product is now ready for market, and is nown as muriate of tin or butter of tin. The hydrate, the solutions and also the anhydrous stannic chlorid whichis found to be loaded with chlorin is now treated for removal of the chlorin and for purposes of further purification the anhydrous may be distilled. When so distilled a still P may be used, from which the vapors may be condensed in an apparatus similar to condenser L. The product of this distillation is then ready for market.

The foregoing heavy chlorids together with the solution of stannic chlorid, coming from the tower, constitute examples of the tin compounds which result from the processes described. It now remains to describe the step by which metallic tin is recovered from the chlorid of tin.

, By referring to Fig. 5, it will be seen that a vat Q is illustrated as containing certain anodes, e,.e, e, etc; which are of the class known as insoluble anodes which are coupled to a common electrical conductor g. The vat Q, together with the connected sheets h, h, It, may constitute the cathode and are provided with electrical connections. The vat Q is surrounded by a jacket F or other suitable means, whereby its tempera: ture may be controlled or maintained at a suitable point. Into this vat is placed the chlorid resulting from the previous steps of the process or such portion thereof as is to be treated for tinin the metallic state or other products. In this ortion of the plant the chlorid and pref drably the hydrated stannic or stannous chlorid solution is electrolized under such conditions that tin is thrown out ordeposited upon the cathodes, h, h, h, etc. The deposit thus se- The crystals are then washed or.

cured from the cathodes may be stripped from the surface thereof or the cathodes themselves may consist of pure metal as in the case of copper refining, inwhich case the base plate as well as the deposited metal may be melted together and cast into ingots for the market. anode compartment is collected and returned to the system through pipe R. The

pipe S. It will be noticed that the process described herein is essentially a continuous one.

. I do not wish to be limited by the foregoirrg method'of recovery of tin from the chlori s, or other compounds of'tin derived from the chlorid. Other methods exist which are urely chemical and-may be employed in lieu of theelectrical method described, and the invention extends to any method by means of which the tin may be thrown out from the compounds of tin obtained either primarily or as a secondary product from the treatment described and claimed herein.-

In the foregoing description of my invention I have set forth-the method of operation, together with its various steps. It should be understood that while the steps are described in the order in which they are employed herein to illustrate one system of procedure, yet

some may be used without the others, and the.

steps may be varied as to detail, as circumstances demand, .and the invention extends to such use.

I claim: 1. The 1process of recovering tin from tin scrap w ich consists inreacting u on the mass to be detinned with chlorin in t e presence of anhydrous stannic chlorid, producing thereby stannic chlorid and throwing out the tin from the chlorid.

2. The process of detinning which consists in treating the mass to be detinned with diluted chlorin in the presence of an anhydrous li uid, heating the gaseous products arising rom the treatment and bringing them into contact with water- 3. The process of detinning whichconsists in treating the mass to be detinned with di luted chlorin in the presence of an anhy drous liquid, cooling the gases rising from such treatment for purpose of condensing the products from same, and then bringing the residual gases into contact with water.

4. The method of detinning which consists in re-acting upon the masses to be detinned with a body of a suitable anhydrous liquid, a itating and supplying chlorin in excess to t e agitated liquid.

5. Theprocess of recovering tin from tin scrap which. consists in reacting u on the mass to be detinned with chlorin in t e presence of anhydrous stannic chlorid and throwirlilg out metallic tin and chlorin from such c orid.

The chlorin coming off the 6. The process: of anhydrous detinning WbiCh:COI1S1StS in subjecting com acted scrap to .the action of a chlorina'te anhydrous liquid and feeding diluted heated chl'orin to the mass.

7. The process of anhydrous detinning which consists in subjecting com acted scrap to the action of a chlorinated anhydrous liquid and diluted heated chlorin beneath the surface of such liquid.

8. The process of detinning which consists in classifying the scrap,'in reacting upon a part of such scrap with chlorin in the presence of a suitable anhydrous liquid and removing the chlorid from the surface of the scrap and recovering same. 1 a

9. The process of detinning which consists in cleansing the scrap by the wet method, drying and then reacting on same with chlorin in the presence of a suitable anhydrous liquid, removing the chlorid from the surface of the scrap and recovering the same.

10. The continuous process of making an hydrous stannic chlorid from tin plate scrap, tin or tin bearing material which consists in submerging such material in a body of liquid anhydrous tin chlorid, and supplying moist chlorin thereto.

11. The method of detinning which consists in reacting upon the masses to be detinned with a body of a suitable anhydrous liquid, agitating and supplying chlorin to the agitated liquid.

12. The method of detinning which consists in reacting upon the masses to be detinned with a body of a suitable anhydrous liquid, agitating both "the masses and the chlorid, supplying chlorin to the agitated mass and controlling the temperature of the reaction.

13. The process. of detinning which consists in compacting the scrap, reacting upon the compacted mass with a chlorinated an- .hydrous liquid while under seal of such '1 liquid, agitating the liquid and feeding chlorm to the agitated mass in excess, whereby the detinning goes forward by chlorin in states of suspension or entrainment and also solution.

14. The process of detinning which consists in treating the mass to be detinned with an anhydrous liquid into which in fed diluted chlorin and bringing the gaseous products arising from the treatment into contact with a solvent therefor.

15. The process of detinning which consists in treating the mass to be detinned with an anhydrous liquid into which is feddiluted chlorin and cooling the gases rising from such treatment and then bringing the residual gases into contact with a solvent therefor.

' 16. The process of detinning which consists in reacting upon the mass to be detinned with chlorin in the presence of an anhydrous li uid, driving off the adhering liquid by dis til lation and recovering the liquid.

17. The process of detinning which consists in cleansing the scrap by the wet method,

drying and then reacting on same with chlorin in the presence of an anhydrous liquid, removing the liquid from the surface of the resultin black scrap and recovering same.

18. Tie process of detinning which consists in cleansing the scrap by the wet method, drying with heat, and then reacting on same while still hot with chlorin in the presence of an anhydrous liquid.

19. The method of detinning which consists in reacting upon the masses to be detinned with a suitable anhydrous liquid, agitating both the masses and the liquid and supplying chlorin to the agitated mass.

20. The continuous process of making anhydrous stannic chlorid from tin plate scrap, tin or tin bearing material which consists in submerging such material in a body of liquid anhydrous tin chlorid and continuously introducing moist chlorin gas beneath the surface of the liquidand simultaneously agitating the mass.

In testimony whereof I have hereunto set my hand in presence of two subscribing Witnesses.

ELMER A. SPERRY.

Witnesses:

C. W. FowLER, N. P. LEONARD. 

